Many coatings, primarily asphaltic based, have been applied from organic solvent solutions to basement walls to provide a water resistant feature to the walls. This application is commonly referred to in the art as "waterproofing". Additionally, it is common to apply protection board to the exterior of a basement wall over such a coating. Foamed polystyrene is used for this purpose as are fiberglass batts. The protective board can also be of sufficient thickness to provide thermal insulation. Such board can also be of assistance in draining water away from the walls.
In order for such basement wall coatings and the solutions containing them to perform satisfactorily and be accepted in the industry there is a need for those materials to possess a wide balance of properties. The coating should possess elastomeric properties, have good strength and toughness and water-resistant qualities. Additionally, since such coatings typically have more than one solid ingredient in the formulation, compatibility of the ingredients is extremely important. Otherwise, over time, separation of the phases or ingredients will result and the coating will become unsatisfactory. Such separation can result in localized areas where the elastomeric properties and the strength or toughness qualities or the water-resistant qualities of the coating would be adversely effected and can also result in insufficient tack to properly hold the protective board to the wall. Local areas of brittleness are also likely to result when separation occurs.
It is generally preferred to apply the protective board to the basement coating while the coating is still wet. Many times, however, it is simply not possible to do this. Consequently, there is a need that the coating, when in the dry condition, also possess an aggressive residual tack to allow, if need be, the application of such protective board after the coating is dry. Because of the lack of residual tack, some systems call for the use of mechanical fastening, e.g. nailing of the protective board to attach it. This is obviously unsatisfactory because it puts holes in the coating. Consequently if such coatings possessed the needed tack there would be no need to jeopardize the integrity of the coating to apply the protective board.
In addition to the coating itself possessing the properties noted above, it is important that there be a proper physiochemical interaction between the coating and the solvent so that the solution itself possesses certain needed properties. Some of these properties are unique to the solvent system itself.
As generally indicated above, it is preferred that the insulating board be applied while the coating is still wet. Consequently, it is extremely important that the solvent system be such that it does not adversely effect, i.e. dissolve, the foamed polystyrene protective board. There is also a need that the coating solution be of a high solids content and that it likewise be of a sprayable viscosity. This is necessary for economical, practical application. This, of course, requires that the solvent system have proper solvation characteristics with respect to the components of the coating.
When the coating is applied there is a need that it not exhibit significant sag, run-down or cobweb formation. Any of such features, if present, severely detrimentally impacts coating quality. While serious sag and run-down are not acceptable, nonetheless, there is also a need that the solution sufficiently fill or wet-out voids and pock marks in the surface of cementitious basement walls. Obviously this balance of properties is not easily attained.
Applicants have found the solvent system also needs to have the proper evaporation rate. (Evaporation rates are well known and are measured by ASTM Test D-3539. The higher the number for the evaporation rate the greater the volatility. As a standard, normal-butyl acetate is given an index of one and other materials are compared to that rate.) If the evaporation rate is too low, for example less than about 1.5 or so, the drying rate is too slow and causes problems in the field. When rates are higher, for example 3.5 and greater, such solvents can cause foaming and cobwebbing problems, either of which result in poor quality coatings.
It is also important that the coating solution maintain consistent properties over the temperature range of application. Since the present coatings are desirably applied by spraying, it will be apparent that viscosity is quite important. Moreover since these type coating solutions are typically applied at elevated temperatures, for example about 105.degree. F. to about 160.degree. F., there is a need that the viscosity in this temperature range be substantially constant.
Finally there is a need that the components of the coating not be prohibitive from a cost point of view.
The present invention provides for a coating and for a coating solution which satisfies these many needs. These coatings possess the needed properties for a, so-called, "waterproofing" coating.